Oria RANF tubing is somewhere between Columbus SL and SP, in terms of weight and butting. I have heard people compare it to SLX/TSX, but that is simply one man's mistake, repeated over and over, on the internet.
It is good, mid-range tubing, on a par with 531 and, as I mentioned, SL and SP. Butted stays give it a nice, not-to-harsh ride.
I inherited an Olmo made with this tubing, and loved it. Not as much as more expensive frames, it was a fine workhorse.
The Shimano 105SC group on your bike, with D/T shifters (should by 7 speed) is from 1990-1992, but I suspect that the frame is actually from the late 80's. I am pretty sure that Daccordi moved to Columbus tubing, by 1990, but am happy to be corrected.
No idea on price - I would pay £150 for this bike, based on what I can see. But I am sucker for steel bikes with chrome.